Method and apparatus for delivering a shape memory article to a surgical site

ABSTRACT

The invention pertains to a method and apparatus for delivering an article formed of a shape memory alloy to a surgical implantation site.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to provisional patent Application No.61/161,604, filed Mar. 19, 2009, the disclosure of which is herebyincorporated herein by reference.

BACKGROUND OF THE INVENTION

Shape memory articles (SMAs), comprised, for instance, substantially ofNiTinol alloy, are used in many surgical applications, including use asstaples for re-attaching tissue or bone. Usually, external heat isapplied to the shape memory article in order to transition it from afirst shape in a martensitic, softer, morphology to a second shape in anaustentitic, stiffer, morphology.

When a patient suffers an injury in which tissue or bone must bereapproximated, reattached, or fused, the injury often must be repairedby surgically securing the tissue or bone together with internalfixation devices such as plates, screws, pins, or staples. These devicesare often rigid and have geometric features that enable them toreapproximate, reattach, or fuse tissues. Examples of these featuresinclude threads, grooves, overall shape of the device, and otherfeatures that provide attachment or support. Any undesired deformationof these devices could lead to increased amounts of strain and ultimatefailure of the device.

Since the late 1980's, NiTinol, a Nickel-Titanium alloy, has beenincreasingly utilized in a variety of medical devices and, in somecases, has become one of the materials of choice for many designers andengineers. From surgical devices to endoluminal stents and otherprostheses, the thermo-mechanical characteristics of the material andits biocompatibility have allowed its use across many medical andsurgical specialties both for diagnostic and therapeutic applications.

The shape memory effect results from a reversible crystalline phasechange known as martensitic transformation. Shape memory alloys candisplay various types of shape memory. The type of shape memory that hasprobably found the most use in commercial applications is commonlyreferred to as one-way shape memory. In one-way shape memory, an articleformed of a shape memory alloy in an original shape can be substantiallyplastically deformed into a shape while it is in the soft, martensiticphase and it will remain in that shape, (hereinafter the deformedshape). Then, upon heating above a first temperature, the materialreturns to its original (prior to deformation) shape while transitioningfrom the soft, martensitic phase to a much stiffer austentitic phase. Itshould be noted that, while the article is much stiffer in theaustentitic phase, it usually is still somewhat deformable, butprimarily elastically, as opposed to plastically, deformable. Uponcooling below a second temperature that is below the first temperature,the material transitions back to the softer, martensitic phase, butmaintains the shape it took during the transformation to the austentiticphase (i.e., its original shape) until it is acted upon by an externalforce or stress. Because the material is less stiff (i.e., more pliable)in its martensitic phase, it is much easier to bend (back to thedeformed shape or any other shape) and it will maintain that new shapeup to and until it is heated once more above its transformationtemperature.

The strength and transition temperatures of SMAs can be greatly variedby changing the exact composition of the alloy and/or the thermalhistory of the article.

The use of shape memory staples in surgical skeletal repair enables astaple to be installed in bone or tissue in one shape while in itsmartensitic phase and then be heated to cause it to transition to themuch stiffer austentitic phase while shifting to another shape that, forinstance, draws the tissue or bone closer together. Many medicalapplications use SMAs having a transition temperature for completemartensitic to austentitic transformation of about 55° C. However, othermedical applications utilize alloys having a complete transitiontemperature at about human body temperature of 37° C.

While metallic staples have long been used for static fixation, the useof shape memory alloys (SMAs) in staples and their attendant ability toapply dynamic continuous compression is a major advancement in tissueand bone uniting that potentially improves the healing process inconnection with the repair, fusing, and remodeling of damaged tissue.These SMA staples are smaller and less bulky than other fixationdevices, such as plates, screws, and nails. They permit smallerincisions, which cause less trauma and scarring and lead to fasterpost-operative recovery. Also, since fewer holes need to be drilled andno screws are needed, more rapid surgical procedures are possible.

The shape memory properties described hereinabove are sometimes referredto as superelasticity, particularly when the transition from martensiticphase to austentitic phase occurs at lower temperatures, such as roomtemperature or below. The terminology is not consistent in the art. Inthis specification, we shall simply use the term shape memorygenerically as encompassing superelasticity.

FIG. 1 is a graph showing a dynamic scanning calorimetry (DSC) for oneparticular NiTinol composition. DSC is useful for determining thetemperatures at which various substances undergo phase changes. In thecase of NiTinol or other SMA articles, DSC is utilized to understand thetemperatures required for transitioning from the martensitic phase tothe austentitic phase and back again. DSC measures the heat flownecessary to maintain the article at a certain temperature. The bottomportion of the scan represents the state of the article at −50° C. as itis subjected to increasing temperature over time. This graph shows astable structure (martensitic morphology) during temperatures up to anaustentitic start temperature (A_(s)) of approximately 29° C., wherephase transformation to the austentitic phase theoretically begins. Asdemonstrated by this scan and the change in heat flow, the metal isfully transformed into its stiff, austentitic phase at the austentiticfinish temperature (A_(f)) of approximately 50° C. The top portion ofthis scan represents cooling of the austentitic NiTinol article startingat 100° C. Note that the martensitic phase recovery theoretically beginsat the martensitic start temperature (Ms) of approximately 19° C. and iscomplete at the martensitic finish temperature of approximately 0° C.This is only an example of one form of NiTinol shape memory alloy. Othertransition temperatures are achievable with different chemicalcompositions and thermo-mechanical treatments.

Using the exemplary material above, one can see that the device isgeometrically stable in its martensitic phase up to room temperature,can be transformed to an austentitic phase via heating it to around 55°C. and that it stays in a stable austentitic phase down to temperatureswell below body temperature. This is very advantageous in surgicalapplications as devices, such as orthopaedic staples, can be programmedduring manufacture with a clinical utility shape in the austentiticphase (the shape that it will take after heating during a surgicalprocedure) and then be deformed during manufacturing to an operableconfiguration in its martensitic phase (the shape in which it will bedelivered to the surgeon for insertion into the body prior to heating).

Orthopaedic NiTinol staples have been available clinically in the US forapproximately ten years. The manufacturers of these devices are usingvarious instruments and power sources for heating the staples in orderto effect the transformation to the austentitic phase in vivo. Tissuecautery and coagulation devices typically are available in an operatingtheater and are commonly used to provide heat to shape memory articles.

Shape memory materials typically have a temperature range of about 20°C. over which they make the transformation from the martensitic phase tothe austentitic phase. Thus, for instance, a shape memory articledesigned to complete its transformation to the austentitic phase at bodytemperature, i.e., about 37° C., will begin transitioning attemperatures as low as 17° C., or at approximately room temperature.

Thus, shape memory articles, particularly ones designed for bodytemperature activation often are exposed to temperatures higher than thetemperature at which they start the phase change from martensitic toaustentitic phase prior to surgery, such as during transportation.Accordingly, shape memory articles often are packaged in themanufacturing plant in a constraining device that prevents them fromchanging shape until released from the constraining device.

Once a shape memory article has transformed to its austentitic phase, itcan be transformed back to martensitic by exposing the shape memoryarticle to a much lower temperature. In the example above, such atransition temperature back to the martensitic phase would occur at orbelow (minus) 15° C. thus, immediately prior to surgery, shape memoryarticles commonly are frozen to return them as fully as possible totheir original martensitic phase and delivered to the operating room ina frozen or other cold state, such as in a cooler filled with ice.

Using a shape memory surgical staple as an example, a surgeon typicallymight remove the staple from its packaging and constraining device whilein its martensitic phase essentially at the time it is needed forimplantation. A surgeon typically might grasp the backspan of the staplewith a clamp and pull it out of the constraining device. The surgeonmight have an extremely small window of time in which to implant thestaple into the patient, e.g., into pre-bored holes in a bone, becausethe staple may start its transformation from the martensitic phase tothe austentitic phase almost immediately upon removal from theconstraining device. Particularly, operating rooms are commonlymaintained at about the austentitic phase transition startingtemperature for body temperature activated shape memory articles.

Even if the operating room is colder than the activation temperature,the surgeon may have to expose the staple to body temperature for aperiod of time before while he is locating the holes within which thelegs of the staple must be inserted, which also could cause the stapleto start deforming before it is in the implantation position.

This can be a significant problem during surgery insofar as, once thestaple or other shape memory article begins deforming, then its legs maynot match up with the pre-bored holes into which they are to beinserted. In such situations, typically, the surgeon would have todiscard the staple and start over with a new staple and move much morequickly.

SUMMARY OF THE INVENTION

The invention pertains to an apparatus for removing a shape memoryarticle, such as a shape memory surgical staple, from its constrainingdevice and delivering it directly to the surgical implantation sitewhile still constraining the shape memory device from deforming untilthe shape memory device is implanted.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a graphical representation of a dynamic scanning calorimetryfor one particular NiTinol composition

FIG. 2 is a perspective view of a shape memory surgical staple disposedin a constraining device pre-surgically.

FIG. 3 is a perspective view of a transfer apparatus in accordance withthe principles of the present invention.

FIGS. 4A-4F illustrate the transfer apparatus of FIG. 3 in variousstages of use.

FIG. 5 is a perspective view of a transfer apparatus in accordance withanother embodiment with a staple partially released therefrom.

FIG. 6 is a perspective view of a shape memory surgical staple packagedpre-surgically in accordance with another embodiment of the presentinvention.

FIG. 7A is a top perspective view of an alternative embodiment of atransfer apparatus in accordance with the principles of the presentinvention in a closed condition.

FIG. 7B is a top perspective view of the transfer apparatus of FIG. 7Ain an open condition.

FIG. 7C is a bottom perspective view of the transfer apparatus of FIGS.7A and 7B.

DETAILED DESCRIPTION OF THE INVENTION

As noted above, shape memory staples and other shape memory articlesoften are packaged in a constraining device so that they do not deformshould they be exposed to temperatures higher than the phase transitionstarting temperature. Nevertheless, shape memory articles must spendsome period of time between being removed from their constrainingpackaging and being fully implanted into bone, tissue, or any otheranatomical feature, during which time the article may deformprematurely, which may make it difficult or impossible to implantcorrectly.

FIG. 2 shows a shape memory staple 500 comprising a backspan 504 withlegs 505 a, 505 b extending substantially orthogonally from the oppositeends of the backspan. The staple is disposed with its legs 505 a, 505 bextending into passages such as holes 501 and 502 in a constrainingdevice 503 and with its backspan without (i.e., outside of) theconstraining device 503. As long as the staple is disposed with its legsin the holes 501, 502 of the constraining device 503, it essentiallycannot deform to any significant extent.

In order to further prevent or minimize the possibility of the shapememory staple 500 (or other shape memory article) from deformingprematurely after it is removed from the constraining device 503, butbefore it is fully implanted, a transfer device is provided such as theexemplary transfer device 506 shown in FIG. 3. In accordance with thisembodiment, the transfer device 506 includes a wedge formation 510 thatprovides a ramp running from a minimal height at its front end 510 a andterminating at a maximum height, H, at its rear end 510 b, as shown inFIG. 3. The transfer device 506 further comprises a passage such asgroove 521 in a major surface 506 a of the transfer device 506 having afirst portion 521 a that conforms to the size and shape of the backspan504 of the staple 500 (at least in terms of the length, L, and thediameter, D, of the backspan 504) and second and third portions 521 b,521 c that each conforms to a proximal portion of the legs of thestaple. The ends of the second and third portions 521 b, 521 c of thegroove are open to a second surface of the transfer device so that thedistal portions of the legs of the staple may extend from the transferdevice from those ends.

As will be described in detail below, the staple will be secured in thegroove 521 from a time prior to removing the staple 500 from theconstraining device 503 up until the staple 500 is implanted.Particularly, with reference to FIG. 4A, when a surgeon is ready todeliver the shape memory staple 500 to the implantation site, the ramp510 of the transfer apparatus is used to partially pull the legs of thestaple out of the holes in the constraining device. Particularly, asshown in FIG. 4A, the surgeon pushes the ramp 510 of the transferapparatus 506 in the direction of arrow A between the backspan 504 ofthe staple 500 and the surface 503 a of the constraining device 503against which the staple backspan is abutted so as to force the backspan504 away from the surface 503 a up to the height H of the ramp. Thisterminal height H of the ramp may be equal to or slightly greater thanthe length of the leg portions of the groove 521 in the transferapparatus.

The transfer apparatus is then pulled back out in the direction oppositeof arrow A to disengage it from the staple 500 and the constrainingdevice 503. At this point, after the ramp has been removed, the shapememory staple still essentially cannot deform from its constrained statesince the ends of the legs 505 a, 505 b are still constrained within theholes 501, 502 of the constraining device 503. Next, the surgeon graspsthe transfer apparatus 506 by the ramp portion 510 and forces the groove521 over the backspan 504 and proximal portions of the legs 505 a, 505 bof the staple 500 as shown in FIG. 4B to lodge the staple 500 in thegroove 521.

With reference to FIG. 3, in one embodiment of the invention, the groove521 may have one or more detents 522 to assure that the staple 500 doesnot inadvertently fall out of the groove after it has been pushed intoit. The detents may, for instance, be narrowed portions of the grooveformed by one or more protrusions in the groove that make that portionof the groove narrower than the diameter D of the wire from which thestaple is formed, which protrusions the staple must be snapped past tobecome seated within the groove 521.

Next, with reference to FIGS. 4B and 4C, the surgeon can pull thetransfer device 506 away from the constraining device 503 in thedirection of arrow C (see FIG. 4B) to pull the distal ends of the staplelegs 505 a, 505 b out and completely free of the constraining device 503(FIG. 4C). At this point, even though the distal ends of the legs 505 a,505 b of the shape memory staple 500 are free, the transfer apparatus506 is constraining the proximal ends of the legs (as well as thebackspan 504) of the staples, thus still substantially preventing thestaple 500 from deforming.

The transfer apparatus 506 can then be used to hold the staple anddeliver the staple to the implantation site. Only after the distal endsof the legs 505 a, 505 b have been inserted into the pre-bored holes atthe implantation site is the staple 500 released from the transferapparatus 506.

For instance, once the distal ends of the legs are reasonably firmlyimplanted in the holes, the staples should be relatively stable suchthat the transfer apparatus can release the staple without inadvertentlyremoving the staple from the holes. If the staple is not sufficientlystable in the implantation holes, the part of the exposed portion of oneof the legs of the staple 500 that is extending from the hole but notwithin the groove 521 of the transfer apparatus 506 can be grasped witha clamp to help stabilize it while the transfer apparatus 506 is snappedoff of the staple 500. The staple can be removed from the transferapparatus 506 by twisting it about an axis substantially perpendicularto the axes of the legs of the staple. For instance, the transferapparatus 506 may first be twisted about the axis of one of the legs,e.g., leg 505 a, of the staple (to snap the other leg 505 b past thedetent 522 and out of the transfer apparatus) as illustrated in FIG. 4D(with arrow 1201 showing the direction of twisting and axis 1200 showingthe axis of twisting. Then, referring to FIG. 4E, the transfer apparatus506 may be twisted in the opposite direction (see arrow 1205 showing thedirection of twisting) about another axis 1203 substantially parallelto, but not collinear with, the axis 1202 of the first leg 505 a to snapthe first leg 505 a past the detent 522 and out of the transferapparatus to completely remove the staple from the transfer apparatus.At this point, the staple 500 can then be pushed fully into the holes,as needed.

Alternately, with reference to FIG. 4F, the transfer apparatus may betwisted about an axis 1207 generally defined by the backspan 504 of thestaple as illustrated by arrow 1206 to snap both legs 505 a, 505 b outof the transfer apparatus simultaneously. Then, the backspan (assumingno detent adjacent the backspan) will simply fall out of the transferapparatus. It should be noted however, that because the backspan ofsurgical shape memory staples typically have a zigzag in them as seen inthe Figures (to allow the backspan to also achieve some compressionduring the transition from martensitic state to austentitic state), ifthe portion 521 a of the channel in the transfer apparatus thataccommodates the backspan is formed as a straight groove and with awidth reasonably close to the diameter of the staple, there may not beenough clearance in that channel portion to permit releasing of thestaple from the transfer apparatus by twisting about the backspan.Specifically, the zigzag in the backspan 504 may hit the wall of thechannel portion 521 a and prevent further twisting before the staple canbe twisted enough to cause the legs 505 a, 505 b to clear the detents522. Since a reasonably tight fit of the backspan 504 in the channelportion 521 a of the transfer apparatus 500 is desirable in order tokeep the staple 500 from sliding in the transfer apparatus in thedirection parallel to the legs 505 a, 505 b of the staple 500 whenseated in the transfer apparatus 506, channel portion 521 a may beshaped eccentrically to accommodate the zigzag and to permit twisting ofthe staple about its backspan. FIG. 5 illustrates such an embodiment. Ascan be seen, the portion of the channel 521 a′ in the transfer apparatus506′ that accepts the backspan 504 of the staple has two portions 1301and 1302 that cause that channel portion 521 a′ to correspond generallyto the zigzag shape of the backspan of the staple. As shown, the channelportion 521 a′ can accommodate the backspan 504 of the staple even whenthe staple is twisted a full 90° out of the transfer apparatus, asshown.

FIG. 5 also illustrates another alternative feature of the transferapparatus. Particularly, in order to enhance the ability of the transferapparatus 500′ to deform to allow the legs 505 a, 505 b of the staple500 to snap past the detents 522 as previously described, grooves 1306,1307 are cut into the material of the transfer apparatus 506′ parallelto the channel portions 521 b, 521 c bearing the detents. This willallow more flex in the material portions 1308, 1309 adjacent thesechannel portions 521 b, 521 c. This feature may be particularlydesirable in connection with transfer apparatus for larger size staples,which transfer apparatus may be larger in size, and therefore inherentlymore rigid.

The transfer apparatus also may be used to remove the staple from thesurgical site in cases where that is necessary. Again, the wedgeformation 510 may be inserted between the backspan of the staple (orother proximal portion of a shape memory article) and the bone (or otheranatomical feature) to which the backspan is adjacent in order to forcethe backspan away from the bone essentially as described above inconnection with the use of the wedge portion to pull the backspan awayfrom the constraining device 503. Once the wedge is inserted so as topush the backspan sufficiently away from the surface, the surgeon cansimply pull the transfer apparatus 506 perpendicularly away from thesurface of the bone. If more force is necessary than can reasonably beapplied via the transfer apparatus, then the surgeon may instead removethe transfer apparatus and grasp the staple with a grasping tool to pullit out.

The transfer apparatus comes in contact with the anatomy at the surgicalsite. Accordingly, it should be made of a biocompatible material,preferably a plastic biocompatible material. The transfer apparatus canbe designed as a re-usable device or as a single use device. If it is tobe reused, it should be fabricated from a material that can withstandrepeated autoclaving processes. Many such materials are well known inthe medical arts.

FIG. 6 illustrates an alternative embodiment of the invention. In thisembodiment, the shape memory article 500 is packaged at the factoryembedded within both a constraining device 555 and a transfer apparatus560 as shown in FIG. 6. In this embodiment, there is no ramp on thetransfer apparatus insofar as the staple backspan and the proximalportion of the legs are already embedded in the groove of the transferapparatus.

In another embodiment, the constraining device may be completelyeliminated. For instance, depending primarily on the size, shape, andshape memory properties of the shape memory device as well as the sizeand shape of the passage in the transfer apparatus relative to the shapememory device, the transfer apparatus may sufficiently restrain theshape memory article so as to completely eliminate the need for aseparate constraining device to hold the distal end of the shape memoryarticle pre-surgically. Accordingly, the shape memory article may simplybe packaged without a constraining device essentially as shown in FIG.4C, i.e., with the proximal end embedded in the transfer apparatus andthe distal end free.

FIGS. 7A-7C illustrate another embodiment of the invention. Thisembodiment is substantially similar to the embodiment described above inconnection with FIGS. 2-3 insofar as the transfer apparatus includes awedge formation 910 and a groove 921 that conforms to the size and shapeof the backspan of the shape memory staple and the proximal portions ofthe legs of the staple. However, rather than having one or more detentsin the groove to assure that the staple does not inadvertently fall outof the groove, this transfer apparatus includes a cover portion 950 thatis slidable between an open position, in which it does not cover theopening of the groove 921 in the major surface 951 of the transferapparatus (the position shown in FIG. 7A) and a closed position, inwhich it does at least partially cover the groove 921 (the positionshown in FIG. 7B). The cover 950 may be shaped, as shown, to provide aconvenient thumb rest for the surgeon when holding the transfer devicewith a staple in it.

In this embodiment, the transfer apparatus is delivered to the surgeonwith the cover 950 in the closed position, as shown in FIG. 7A. Thecover would remain in this closed position throughout the entiresurgical procedure until the time when the transfer apparatus is to bedetached from the staple (e.g., after the distal portions of the legs ofthe staple have been inserted into the holes in the anatomical featurein which it will be implanted). Then, the surgeon can slide the cover950 back with his thumb and simply translate the transfer apparatus inthe direction represented by arrow B in FIG. 7B, i.e., parallel to themajor surface 951, to disengage the transfer apparatus from the staple.An advantage of this embodiment is that the detents may be eliminated sothat the entire groove 921 is sized slightly larger than the diameter ofthe staple so that no force need be applied to the staple when removingthe transfer apparatus from the staple after partial implantation.

The slidable cover 950 may be attached to the main body of the transferapparatus by any reasonable mechanism that would allow it to slide. Forinstance, in one embodiment illustrated in FIG. 7C, a slot 955 isprovided in the aforementioned major surface 951 and completely throughto the opposing major surface 922 of the transfer apparatus 906 and acorresponding pin 957 is provided on the underside of the cover 950 tomate with the slot 955 and slide in the slot. The distal-most portion ofthe pin 957 may be enlarged to form a button, ball, T shaped extensionor other form of flange 958 with a diameter larger than the width of theslot so that the flange 957 is trapped in the slot 955 to hold the cover950 to the main portion of the transfer apparatus, but allow it to slidein the slot 955.

In the embodiment illustrated in FIGS. 7A-7C, the cover 950 covers onlythe backspan portion of the groove 921. However, in other embodiments,it can cover the entire groove, including the portions that hold theproximal portions of the legs of the shape memory staple. This mightprovide more support for the staple and, particularly, prevent it fromrocking about an axis parallel to the legs of the staple duringimplantation.

In another embodiment, the features of the embodiment of FIG. 5 allowingeasier removal of the staple by providing grooves 1306, 1307 paralleland adjacent the channel portions 521 b, 521 c that allow the materialportions 1308, 1309 that bear the detents 522 to flex more easily (seeFIG. 5) may be combined with the cover feature of the embodiment ofFIGS. 7A-7C. In fact, in yet another embodiment, the grooves 1306, 1307may be reduced to nominal size such that there is a very small gap or noactual gap between material portions 1308, 1309 and middle materialportion 1311. Instead, material portion 1311 (or at least a substantialportion of it extending up to the front surface) may be integral with orattached to the cover so that it slides back with the cover. Thus, whenthe cover is in the closed position covering backspan channel portion521 a, the staple is held securely in the channel by detents 522 becausematerial portions 1308, 1209 bearing the detents cannot move becausethey are blocked by material portion 1311. However, when the cover isslid open to reveal the backspan channel 521 a, the material portion1311 also slides back so that it no longer blocks material portions1308, 1309. Material portions 1308, 1309 may be slidable medially oncematerial portion 1311 is moved away. Alternately, they may be flexibleas described in connection with the embodiment of FIG. 5. Of course, insuch an embodiment, material portion 1311 would need to be speciallyshaped and attached to the cover to provide clearance to slide backwithout being blocked by the backspan of the staple held in the channelportion 521 a. For instance, material portion 1311 could be attached tothe cover via the flange 958 adjacent the back surface 922 (asillustrated in the embodiment of FIG. 7C) and material portion could beshallower in depth so as not to extend all the way to front surface 951so as not to interfere with the staple. Furthermore, another channelwould need to be provided in the transfer apparatus into which materialportion 1311 would slide when the cover is opened.

Having thus described a few particular embodiments of the invention,various alterations, modifications, and improvements will readily occurto those skilled in the art. Such alterations, modifications, andimprovements as are made obvious by this disclosure are intended to bepart of this description though not expressly stated herein, and areintended to be within the spirit and scope of the invention.Accordingly, the foregoing description is by way of example only, andnot limiting. The invention is limited only as defined in the followingclaims and equivalents thereto.

1. An apparatus for holding a shape memory article, the shape memoryarticle comprising a proximal portion and a distal portion and adaptedto be implanted into an anatomical feature with the distal portionfirst, the apparatus comprising: a body having a passage for receivingthe proximal portion of the shape memory article, the passage shaped tosubstantially prevent the shape memory article from deforming inaccordance with its shape memory properties when the proximal portion ofthe shape memory article is positioned in the passage.
 2. The apparatusof claim 1 wherein the passage is shaped and sized so that the distalportion of the shape memory article can be implanted into an anatomicalfeature while the shape memory article is positioned in the passage ofthe apparatus.
 3. A combination comprising the apparatus of claim 2 andthe shape memory article.
 4. The combination of claim 3 wherein theshape memory article is a medical staple and wherein the proximalportion of the staple comprises a backspan and proximal portions of legsextending from the backspan, and the distal portion of the staplecomprises distal portion of the legs.
 5. The combination of claim 3wherein the passage comprises a first groove on a surface of theapparatus.
 6. The combination of claim 5 wherein the first groovecomprises at least a portion bearing a detent adapted to hold the shapememory article in the groove.
 7. The combination of claim 6 wherein thedetent comprises an overhang defining a clearance that is less than adiameter of a section of the proximal portion of the shape memoryarticle.
 8. The combination of claim 6 further comprising a secondgroove in the apparatus positioned and shaped to enhance flexibility ofa portion of the apparatus adjacent to a portion of the first groovebearing the detent for permitting the shape memory article to be forcedpast the detent.
 9. The combination of claim 8 wherein the first groovecomprises a first portion adapted to receive a backspan of the shapememory staple and second and third portions adapted to receive proximalportions of first and second legs of the medical staple, respectively,the second and third portions of the first groove each having a lengthand wherein the detent comprises first and second detents in the secondand third portions of the first groove, respectively, and wherein thesecond groove comprises two grooves parallel to the second and thirdportions of the first groove.
 10. The apparatus of claim 1 furthercomprising a cover movable between a closed position in which the covercovers at least a portion of the passage so as to prevent a shape memoryarticle positioned in the passage from being removed from the passageand a second position in which the cover does not cover the passage sothat a shape memory article positioned in the passage can be removedfrom the passage.
 11. The apparatus of claim 10 wherein the cover isslidably attached to the body.
 12. A combination comprising theapparatus of claim 11 and the shape memory article, wherein the shapememory article is a medical staple and wherein the proximal portion ofthe staple comprises a backspan and proximal portions of legs extendingfrom the backspan, and the distal portion of the staple comprises distalportion of the legs and wherein the passage comprises a groove on asurface of the apparatus and wherein the cover covers the surface of thetransfer device above the groove when in the closed position and doesnot cover the surface of the transfer device above the groove when inthe closed position.
 13. The combination of claim 12 wherein the groovecomprises a first portion adapted to receive a backspan of the shapememory staple and second and third portions adapted to receive proximalportions of first and second legs of the medical staple, respectively,the first portion of the groove shaped eccentrically to accommodate azigzag shaped backspan of the staple during twisting of the staple aboutan axis generally parallel to the backspan.
 14. A combination of theapparatus and shape memory article of claim 3 in further combinationwith a constraining device, the constraining device comprising a passagesized and shaped to receive the distal portion of the shape memoryarticle so as to substantially prevent the distal portion of the shapememory article from deforming.
 15. The combination of claim 14 whereinthe apparatus comprises a first surface from which the distal portion ofthe shape memory article will extend when the proximal portion of theshape memory article is positioned in the passage in the apparatus, andthe constraining device comprises a second surface from which theproximal portion of the shape memory article will extend when the distalportion of the shape memory article is positioned in the passage in theconstraining device.
 16. The combination of claim 15 wherein the firstsurface of the apparatus and the second surface of the constrainingdevice abut when the proximal portion of the shape memory article ispositioned in the apparatus and the distal portion of the shape memoryarticle is positioned in the passage of the constraining device.
 17. Thecombination of claim 15 wherein the shape memory article comprises amedical staple having a backspan and first and second legs extendingfrom the backspan, the first and second legs having proximal portionsadjacent to the backspan and distal portions and wherein the passage inthe constraining device comprises two bores positioned, sized, andshaped to receive the distal ends of the first and second legs of themedical staple.
 18. The apparatus of claim 1 further comprising a firstsurface from which the distal portion of the shape memory article willextend when the proximal portion of the shape memory article ispositioned in the passage in the apparatus and a grasping portionextending away from the passage in a direction opposite from the firstsurface.
 19. The apparatus of claim 1 further comprising a ramp portion.20. The apparatus of claim 19 wherein the passage defines a depth of theshape memory article that must be exposed in order for the shape memoryarticle to be received in the passage and wherein the ramp portion has amaximum height substantially equal to the depth.
 21. The apparatus ofclaim 19 wherein the shape memory article comprises a medical staplehaving a backspan and first and second legs extending from the backspan,the first and second legs having proximal portions adjacent to thebackspan and distal portions and wherein the ramp portion has a maximumheight and wherein the passage in the apparatus is adapted to receivethe backspan and the proximal portions of the less of the medical stapleand wherein the passage in the apparatus comprises a groove in a firstsurface of the apparatus, the groove comprising a first portion adaptedto receive the backspan of the medical staple and second and thirdportions adapted to receive the proximal portions of the first andsecond legs of the medical staple, the second and third portions of thegroove each having a length and extending and open to a second surfaceof the apparatus from which the distal portions of the legs of themedical staple will extend when the maximal portion of the medicalstaple is positioned within the passage and wherein the length of thesecond and third portions of the groove is substantially equal to themaximum height of the ramp.
 22. A method of handling a shape memorystaple comprising a backspan and first and second legs, the legs havingproximal portions attached to the backspan and distal portions, themethod comprising: placing the distal portions of the legs of the staplein at least one passage in a constraining device that substantiallyconstrains the legs from deforming; placing the proximal portions of thelegs of the staple in at least one passage in a apparatus that,independently of the constraining device, substantially prevents thelegs from deforming.
 23. The method of claim 22 wherein the passage inthe apparatus comprises a groove in a first surface of the apparatus,the groove comprising a first portion adapted to receive a backspan ofthe shape memory staple and second and third portions adapted to receiveproximal portions of first and second legs of the medical staple, thesecond and third portions of the groove each having a length andextending and open to a second surface of the apparatus, the methodfurther comprising: pulling the apparatus away from the constrainingdevice to release the distal portions of the legs of the staple from theconstraining device; and implanting the distal portions of the legs ofthe staple in an anatomic feature while holding the staple via theapparatus.
 24. The method of claim 23 further comprising: removing thestaple from the apparatus after the distal portions of the legs areimplanted.
 25. The method of claim 24 further comprising: pushing thestaple further into the anatomical feature after the staple is removedfrom the apparatus.
 26. The method of claim 24 wherein the removing ofthe staple from the apparatus comprises removing the staple from thegroove through the first surface of the apparatus.
 27. The method ofclaim 26 wherein the removing comprises rotating the apparatus relativeto the staple about an axis substantially parallel to the first andsecond legs of the staple.
 28. The method of claim 26 wherein theremoving comprises: rotating the apparatus relative to the staple abouta first axis substantially collinear with the first leg of the staple toremove the second leg of the staple from the groove; and subsequentlyrotating the apparatus relative to the staple about a second axissubstantially parallel and not collinear with the first leg of thestaple to remove the first leg from the groove.
 29. The method of claim26 wherein the removing comprises: rotating the apparatus relative tothe staple about an axis substantially parallel to the backspan of thestaple to remove the first and second legs of the staple from thegroove; and after the rotating, pulling the apparatus away from thestaple.
 30. The method of claim 26 wherein the apparatus furthercomprises a cover movable between a closed position in which the covercovers at least a portion of the passage so as to prevent the staplefrom being removed from the passage and a second position in which thecover does not cover the passage so that the staple can be removed fromthe passage, the method further comprising: maintaining the cover in theclosed position during the pulling; and moving the cover into the openposition prior to the removing.
 31. A method of handling a shape memorystaple, the shape memory staple comprising a backspan and first andsecond legs, the legs having proximal portions attached to the backspanand distal portions, the method comprising: placing the legs of thestaple in at least one passage in a constraining device thatsubstantially constrains the legs from deforming, the backspan of thestaple positioned without the constraining device but adjacent a firstsurface of the constraining device; inserting a ramp of an apparatusbetween the backspan and the first surface of the constraining device toforce the backspan away from the first surface of the constrainingdevice and expose a proximal portion of the legs without theconstraining device; placing the proximal portions of the legs of thestaple in a passage in the apparatus that, independently of theconstraining device, substantially prevents the legs from deforming; andpulling the apparatus away from the constraining device to releasedistal portions of the legs of the staple from the constraining device.32. The method of claim 31 further comprising: implanting the distalportions of the legs of the staple in an anatomic feature while holdingthe staple via the apparatus.
 33. The method of claim 32 furthercomprising: removing the staple from the apparatus after the distalportions of the legs are implanted.
 34. The method of claim 33 furthercomprising: pushing the staple further into the anatomical feature afterthe staple is removed from the apparatus.
 35. The method of claim 33wherein the passage in the apparatus comprises a groove in a firstsurface of the apparatus, the groove comprising a first portion forreceiving a backspan of the medical staple and second and third portionssubstantially perpendicular to the first portion for receiving proximalportions of first and second legs of the medical staple, respectively,and wherein the removing of the staple from the apparatus comprisesremoving the staple from the groove through the first surface of theapparatus.
 36. The method of claim 35 wherein the apparatus furthercomprises a cover movable between a closed position in which the covercovers at least a portion of the groove in the first surface of theapparatus so as to prevent the staple from being removed from the grooveand a second position in which the cover does not cover the groove sothat the staple can be removed from the groove, the method furthercomprising: maintaining the cover in the closed position during thepulling; and moving the cover into the open position prior to theremoving.
 37. The method of claim 35 wherein the removing comprisesrotating the apparatus relative to the staple about an axissubstantially parallel to the second and third portions of the groove ofthe apparatus.
 38. The method of claim 35 wherein the removingcomprises: rotating the apparatus relative to the staple about a firstaxis substantially collinear with the second portion of the groove toremove the second leg of the staple from the groove; and subsequentlyrotating the apparatus relative to the staple about a second axissubstantially parallel and not collinear with the second portion of thegroove to remove the first leg of the staple from the groove.
 39. Themethod of claim 35 wherein the removing comprises: rotating theapparatus relative to the staple about an axis substantially parallel tothe first portion of the groove of the apparatus to remove the first andsecond legs of the staple from the groove; and after the rotating,pulling the apparatus away from the staple.